#绘制一个长方形的简单代码
from turtle import *

#设置笔刷宽度
width(4)
#前进
forward(200)
#右转90度
right(90)

#笔刷颜色：
pencolor('red')
forward(100)
right(90)

pencolor('blue')
forward(200)
right(90)

pencolor('yellow')
forward(100)

done()

def drawStar(x, y):
    pu()
    goto(x, y)
    pd()
    # set heading: 0 小乌龟启动时运动的方向
    seth(0)
    for i in range(5):
        fd(40)
        rt(144)

for x in range(0, 250, 50):
    drawStar(x, 0)

done()



# 设置色彩模式是RGB:
colormode(255)

lt(90)

lv = 14
l = 120
s = 45

width(lv)

# 初始化RGB颜色:
r = 0
g = 0
b = 0
pencolor(r, g, b)

penup()
bk(l)
pendown()
fd(l)

def draw_tree(l, level):
    global r, g, b
    # save the current pen width
    w = width()//设置笔刷宽度

    # narrow the pen width
    width(w * 3.0 / 4.0)
    # set color:
    r = r + 1
    g = g + 2
    b = b + 3
    pencolor(r % 200, g % 200, b % 200)

    l = 3.0 / 4.0 * l

    lt(s)
    fd(l)

    if level < lv:
        draw_tree(l, level + 1)
    bk(l)
    rt(2 * s)
    fd(l)

    if level < lv:
        draw_tree(l, level + 1)
    bk(l)
    lt(s)

    # restore the previous pen width
    width(w)

speed("fastest")

draw_tree(l, 4)

done()
